| Front device -> Monitor Keywords |
|
|
  Front deviceRelated Patent Categories: Excavating, Digging EdgeThe Patent Description & Claims data below is from USPTO Patent Application 20070124963. Brief Patent Description - Full Patent Description - Patent Application Claims
TECHNICAL FIELD [0001] This invention relates to a front device that is mounted on a construction machine, such as a hydraulic excavator or a hydraulic crane, and is appropriately employed, for example, as a boom or an arm for a working mechanism. BACKGROUND ART [0002] Generally, for a construction machine such as a hydraulic excavator or a hydraulic crane, a working mechanism for performing excavating or loading, for example, is liftably provided. As such a working mechanism, a hydraulic excavator that includes a front device such as a boom or an arm is well known (e.g., see Japanese Patent Laid-Open No. 2001-81810). [0003] Consider the boom of a hydraulic excavator as an example of a front device according to this first prior art. This boom includes a box member, which is formed as a hollow structure having the shape of a box by welding together an upper flange, a lower flange, a left web and a right web, and a boss which is located on the base end of the box member, and is liftably coupled with the vehicle body of a hydraulic excavator. [0004] In this case, the boss is formed by a cylinder which is made of a metallic material having a high strength, and the ends of the upper flange, the lower flange, the left web and the right web of the box member are welded at the external surface. Further, a bracket which the arm of the working mechanism is rotatably connected is provided at the distal end of the box member. [0005] Furthermore, according to the first prior art, various reinforcement structures are provided to obtain the strength of the hollow box member. In this case, in the first prior art, for example, a concave rib is formed at the middle position in the longitudinal direction of the left web of the boom. [0006] Further, as a second prior art, a structure is well known wherein, for example, the upper flange, the lower flange, the left web and the right web of a box member are formed of thick steel plates, and a blocking plate is provided inside of the box member to block the internal space at the middle position in the longitudinal direction (e.g., Japanese Patent Laid-Open No. Sho 53-31539). [0007] In the first prior art mentioned above, since the boss which has a high strength is welded to the upper flange, the lower flange, the left web, the right web which have lower strengths, there is a demand at this stage in the designing of a front device that the strength be obtained at the position whereat these two materials which have different strengths are welded together. [0008] However, according to the structure of the first prior art, the rib is located in the middle in the longitudinal direction of the left web of the boom. The rib can increase the flexural strength of the left web, but there is a limit to greatly increasing the strength of the box member as a whole. Thus, there is a problem that it is difficult for a satisfactory strength to be obtained near the boss. [0009] Further, according to the structure of the second prior art, the upper flange, the lower flange, the left web and the right web of the box member are formed of thick steel plates and the blocking plate is provided inside. However, when thick steel plates are simply employed, the weight of the boom is increased, which causes problems, i.e., an increase in the size of an actuator that drives the boom and results in the reduction of the operation efficiency. In addition, even when the blocking plate is provided inside of the box member, the strength may be insufficient near the boss because this blocking plate is located separate from the boss. DISCLOSURE OF THE INVENTION [0010] In the view of the above described problems with the prior art, it is an object of the present invention to provide a front device that can suppress an increase in the weight of a box member, can easily improve the strength of the box member in the vicinity of a boss, and can improve durability. [0011] (1) To achieve the above described objective, the present invention is applied for a front device including a box member formed by welding together an upper flange, a lower flange, a left web and a right web, and a boss located at least at one end of the box member and welded to the ends of the upper flange, the lower flange, the left web and the right web. [0012] And the characteristics of the arrangement adopted by the present invention are that a bent plate portion which is bent inward is provided for at least one side web of the left web or the right web, and a reinforcement plate is located outside of the bent plate portion and arranged between the one side web and the boss. [0013] According to this arrangement, at the position on the end side to be welded to the boss, the bent plate portion can be provided for either the left web or the right web of the box member, or for both the left and right webs, and the reinforcement plate can be located outside of the bent plate portion. Therefore, since the portions of the box member to be welded to the boss can obtain a double structure by use of the bent plate portion and the reinforcement plate, the strength of this portion can be increased, and a high rigidity can also be obtained to an external force in a torsional direction. [0014] In this case, the boss is formed as a metallic cylindrical member having a high strength. Whereas the upper flange, the lower flange, the left web, the right web which constitute the box member are made of steel plates and have a lower strength than the boss. Thus, it is preferable that the portion whereat the two materials having the different strengths are welded be formed at a high strength. Therefore, when the bent plate portion and the reinforcement plate are arranged at the end side of the box member, the portion whereat two materials having different strengths are welded can be appropriately protected. [0015] Furthermore, since the reinforcement plate is located outside of the bent plate portion, for example, the portions of the left web or the right web which are other than the bent plate portion and the reinforcement plate can be arranged continuously and substantially on the same vertical plane. Therefore, since the reinforcement plate does not greatly project outside of the box member, the front device can be made compactly, and a high rigidity can be obtained. [0016] And, since the necessary portions of the box member can be reinforced by use of the bent plate portion and the reinforcement plate, the upper flange, the lower flange, the left web and the right web having a minimum required thickness can be used at positions separate from the boss. As a result, in the vicinity of the boss, a high strength that can not be obtained by employing a rib, a blocking plate, etc., is ensured, and the weight of the box member as a whole can be held down, so that a small, light and very durable front device can be provided. [0017] (2) In addition, according to the arrangement of the present invention, a bent plate portion which is bent inward is provided for at least one side flange of the upper flange or the lower flange, and a reinforcement plate is located outside of the bent plate portion and arranged between the one side flange and the boss. [0018] Since the bent plate portion is provided for either the upper flange or the lower flange of the box member, or for both upper and lower flanges, and the reinforcement plate can be arranged, the portion to be welded to the boss can provide a double structure, and the strength of the box member can be increased at this place. Further, since the reinforcement plate does not greatly project outside of the box member, the front device can be made compactly. Therefore, in the vicinity of the boss, a high strength which can not be obtained by employing a rib, a blocking plate is ensured, and the weight of the box member as a whole can be held down, so that a small and light front device having a high strength can be provided. [0019] (3) Further, according to the arrangement of the present invention, one bent plate portion which is bent inward is provided for at least one side web of the left web or the right web, and another bent plate portion which is bent inward is provided for at least one side flange of the upper flange or the lower flange, one reinforcement plate is located outside of the one bent plate portion and arranged between the one side web and the boss, and another reinforcement plate is located outside of the other bent plate portion and arranged between the one side flange and the boss. [0020] Thus, since the bent plate portion is provided for the upper flange or the lower flange of the box member, and the reinforcement plate can be arranged thereat, and since the bent plate portion is provided for the left web or the right web, and the reinforcement plate can be arranged thereat, the above described two effects can be obtained. Further, for example, the bent plate portions are provided for the upper flange, the lower flange, the left web and the right web individually, and the reinforcement plates can be arranged outside of the individual bent plate portions. According to this arrangement, for example, the upper and lower bent plate portions and the left and right bent plate portions can be welded together to form a shape like a box, and the four upper, lower, left and right reinforcement plates can be welded to form a shape like a box at the position which enclose the bent plate portions from outside. In this manner, a box member shaped like a double box can be formed in the vicinity of the boss, and at this position, the strength of the front device can be appropriately increased. [0021] (4) Further, according to the present invention, the box member serves as at least one component of a lower boom which is liftably coupled with the body of a construction machine, an upper boom which is pivotally coupled with the distal end of the lower boom for swinging movements in leftward and rightward directions, or an arm which is rotatably coupled with the distal end of the upper boom through an arm support member and to which a work tool is attached. Continue reading... Full patent description for Front device Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Front device patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Front device or other areas of interest. ### Previous Patent Application: Magnetic blade attachment in an ice conditioning machine Next Patent Application: Compact excavator implement interface Industry Class: Excavating ### FreshPatents.com Support Thank you for viewing the Front device patent info. IP-related news and info Results in 1.49043 seconds Other interesting Feshpatents.com categories: Qualcomm , Schering-Plough , Schlumberger , Seagate , Siemens , Texas Instruments , |
||
